Characteristics of regulated power supply
1. Three-phase AC voltage regulator has low price, low power consumption and high efficiency. In the switched three-phase AC voltage regulator circuit in FIG. 1, the transistor V, under the excitation of the excitation signal, works alternately in the on-off and off-on switch states, the conversion speed is very fast, and the frequency is generally Around 50kHz, in some technologically advanced countries, it can be several hundred or nearly 1000kHz. This makes the power consumption of the switching transistor V very small, the efficiency of the power supply can be greatly improved, and its efficiency can reach 80%.
2. Small size and light weight. It can be clearly seen from the block diagram of the switching power supply that there is no bulky power frequency transformer. Since the dissipated power on the adjusting tube V is greatly reduced, a larger heat sink is omitted. For these two reasons, the switching power supply is small and light.
3. Wide voltage range. The output voltage of the three-phase AC voltage regulator from the switch is adjusted by the duty cycle of the excitation signal. The change of the input signal voltage can be compensated by frequency modulation or width adjustment. In this way, when the power frequency grid voltage changes greatly, It can still guarantee a more stable output voltage. Therefore, the voltage stabilizing range of the switching power supply is wide, and the voltage stabilizing effect is very good. In addition, there are two methods of changing the duty ratio: pulse width modulation type and frequency modulation type. In this way, the switching power supply not only has the advantages of a wide range of voltage regulation, but also has many ways to achieve voltage regulation. Designers can flexibly choose various types of switching power supply according to the requirements of actual applications.
4. The efficiency of filtering is greatly improved, and the capacity and volume of the filtering capacitor are greatly reduced. The operating frequency of the switching power supply is basically working at 50kHz, which is 1000 times that of the linear power supply, which makes the filtering efficiency after rectification almost increased by 1000 times. Even with half-wave rectification and capacitor filtering, the efficiency is increased by 500 times. Under the same ripple output voltage, when using a switching power supply, the capacity of the filter capacitor is only 1/500—1/1000 of the filter capacitor in the linear power supply.
5. The circuit form is flexible and diverse. For example, there are self-excited type and other excited type, there are width-adjusted type and frequency-adjusted type, there are single-ended type and double-ended type, etc., designers can take advantage of various types of circuits to design switches that can meet different applications Power Supply.